Resizing windows behaviour?

[ac]

Using Ubuntu 12.04 (updated) I suddenly find, presumably after a
recent update (?), that when I resize displayed windows - using a left
mouse click at one corner and drag, then BOTH sides of the window
move, say, left & right, or top & bottom. Previous behaviour was that
only the corner being actively grabbed and its associated boundaries,
moved. I find the recent change, where now, both sides change
position, pretty inconvenient. I need to resize windows to FIT a
particular space, I never need to ONLY make a window smaller keeping
its centre point still. It seems to me it is a Ubuntu change, not
certain programs.
Anyone know if this 'improved' (?) behaviour can be turned OFF please?
tia